1 files changed, 42 insertions, 7 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index eab9c4213b49..82815cff15a9 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -294,18 +294,26 @@ static int acpi_video_device_set_state(struct acpi_video_device *device, int sta
 static int acpi_video_get_brightness(struct backlight_device *bd)
 {
 	unsigned long cur_level;
+	int i;
 	struct acpi_video_device *vd =
 		(struct acpi_video_device *)bl_get_data(bd);
 	acpi_video_device_lcd_get_level_current(vd, &cur_level);
-	return (int) cur_level;
+	for (i = 2; i < vd->brightness->count; i++) {
+		if (vd->brightness->levels[i] == cur_level)
+			/* The first two entries are special - see page 575
+			   of the ACPI spec 3.0 */
+			return i-2;
+	}
+	return 0;
 }
 
 static int acpi_video_set_brightness(struct backlight_device *bd)
 {
-	int request_level = bd->props.brightness;
+	int request_level = bd->props.brightness+2;
 	struct acpi_video_device *vd =
 		(struct acpi_video_device *)bl_get_data(bd);
-	acpi_video_device_lcd_set_level(vd, request_level);
+	acpi_video_device_lcd_set_level(vd,
+					vd->brightness->levels[request_level]);
 	return 0;
 }
 
@@ -702,7 +710,6 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
 	kfree(obj);
 
 	if (device->cap._BCL && device->cap._BCM && device->cap._BQC && max_level > 0){
-		unsigned long tmp;
 		int result;
 		static int count = 0;
 		char *name;
@@ -711,11 +718,10 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
 			return;
 
 		sprintf(name, "acpi_video%d", count++);
-		acpi_video_device_lcd_get_level_current(device, &tmp);
 		device->backlight = backlight_device_register(name,
 			NULL, device, &acpi_backlight_ops);
-		device->backlight->props.max_brightness = max_level;
-		device->backlight->props.brightness = (int)tmp;
+		device->backlight->props.max_brightness = device->brightness->count-3;
+		device->backlight->props.brightness = acpi_video_get_brightness(device->backlight);
 		backlight_update_status(device->backlight);
 		kfree(name);
 
@@ -1324,8 +1330,37 @@ acpi_video_bus_write_DOS(struct file *file,
 
 static int acpi_video_bus_add_fs(struct acpi_device *device)
 {
+	long device_id;
+	int status;
 	struct proc_dir_entry *entry = NULL;
 	struct acpi_video_bus *video;
+	struct device *dev;
+
+	status =
+	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
+
+	if (!ACPI_SUCCESS(status))
+		return -ENODEV;
+
+	/* We need to attempt to determine whether the _ADR refers to a
+	   PCI device or not. There's no terribly good way to do this,
+	   so the best we can hope for is to assume that there'll never
+	   be a video device in the host bridge */
+	if (device_id >= 0x10000) {
+		/* It looks like a PCI device. Does it exist? */
+		dev = acpi_get_physical_device(device->handle);
+	} else {
+		/* It doesn't look like a PCI device. Does its parent
+		   exist? */
+		acpi_handle phandle;
+		if (acpi_get_parent(device->handle, &phandle))
+			return -ENODEV;
+		dev = acpi_get_physical_device(phandle);
+	}
+	if (!dev)
+		return -ENODEV;
+	put_device(dev);
+
 
 
 	video = acpi_driver_data(device);